Primary care physicians are uncertain about diagnostic choices in patients with chest pain suggestive of ischemic heart disease. There are several reasons for this: 1) the accuracy of several noninvasive tests (exercise tolerance testing, exercise thallium scintigraphy, and exercise echocardiography) in primary care settings has yet to be established; 2) the value of clinical signs and symptoms for estimating the prior probability of coronary artery disease is unclear; 3) the utilities patients and physicians have for diagnostic information is unknown. This study seeks to improve the diagnosis and, therefore, the outcome of patients in the primary care system with suspected angina. We will prospectively enroll 500 patients from primary care physicians' offices in Rochester, New York. Each patient will have multiple noninvasive tests and the results will be interpreted blind to other tests. Some patients will go on to coronary angiography (as clinically indicated). All will be followed to determine their clinical course and functional status outcomes. The accuracy of the diagnostic tests will be calculated with reference to this information, utilizing ROC analysis. Data will also be collected about the value patients and physicians place on diagnostic information. A decision analysis will be used to determine the diagnostic approaches which are preferred based on expected outcomes and cost-effectiveness considerations in patients characterized by their presenting symptoms. Information from this project will be linked to that from the stable angina PORT project to develop guidelines for more informed diagnostic decision making in primary care settings. The impact of this should extend beyond diagnostic testing and lead to the more efficient use of percutaneous transluminal angioplasty, and coronary artery bypass graft surgery.